Introduction:Various studies have been done on triceps brachii muscle but the description of the highest extent of lateral and medial head of triceps brachii muscle remained unexplored that is why this study was undertaken to know the extent of their proximal attachments in relation to anatomical neck of humerus and capsule of shoulder joint. Materials and Methods: The shoulder region of 50 formalin fixed upper limbs were dissected to explore the capsule of shoulder joint to reach the highest extent of lateral & medial head of triceps brachii muscle where the nature of fibres, fleshy or tendinous was noted. Oblique and vertical distances of proximal attachment of lateral & medial head of triceps brachii muscle to the anatomical neck of humerous was measured with the help of a sliding caliper. Results: Medial head of triceps brachii muscle in all the cases was fleshy in origin while that of lateral head; fibres were fleshy and tendinous in 82% & 18% of cases, respectively. Fibres of lateral and medial head were blending with the capsule of shoulder joint in 28% & 6% of cases respectively. Maximum cases of lateral head were having their oblique and vertical distances between 21-40 mm (64% & 58% respectively) while those for medial head were >40 mm (68% & 74% respectively). Conclusion: Accurate knowledge of these anatomical patterns of triceps brachii muscle are of considerable clinical importance in the conduct of reparative open access and arthroscpic surgeries around the shoulder and the fracture management of the upper end of humerus.